Location detection of third parties can be a valuable tool in a variety of circumstances. For example, it may be extremely valuable for parents to be able to locate their children. Similarly, location detection can be valuable in protecting persons having limited and/or reduced capacity, such as elderly and/or disabled people. Other contexts where location detection can be valuable can include military and/or law enforcement applications where knowing the specific location of an individual can be beneficial.
The evolution of location detection capable devices such as cellular telephones, global positioning system (GPS) receivers, and radio frequency identification (RFID) devices has improved the capacity to perform location-based tracking of an individual. Such devices, however, may be limited in that they can provide the location of the device and provide no information as to the identity of the person, if any, with the device. Some approaches for overcoming this shortcoming can include requiring a user to use a code key to verify his identity. In the case of a physical code key, such as a device having an encrypted identification code, the issue of whether or not the user is with the device can be unresolved. Other approaches can use a response code that can be entered by a user to verify his identity. The response code, however, can be compromised, surreptitiously, and/or coercively, and be used by a non-user. Additionally, some location tracking devices can be contained within small, concealable devices such as a wristwatch or identification tag and thus do not otherwise provide an interface for code entry. For example, a small, concealable device may not include a display and/or keypad that may be necessary for entering such a code.